The invention relates to an evaporator assembly.
A conventional evaporator is normally a fabrication of tubes and fins, but not necessarily so, wherein refrigerant is circulated through the tubes and a heat source for example ambient air, although other heat sources are known, is propelled through the tube-fin fabrication wherein thermal transfer takes place in the known manner from the higher temperature heat source to the lower temperature refrigerant.
This is a well known and well established function.
It is also well known that at low temperatures and in conditions of high relative humidity the moisture content in the heat source and the low temperature tube-fin fabrication combine to produce a frost or ice deposit on the tube-fin fabrication presenting a resistance to thermal transfer and obstructing the passage of the heat source through the tube-fin fabrication.
This condition is particularly pertinent to conventional evaporators when employed in vapour compression thermal transfer units such as heat pumps and the corrective action in general use is to reverse the vapour compression cycle as in the well known reverse-cycle technique whereby hot refrigerant gas is propelled through the evaporator tubes with the resultant melting of the frost or ice deposit.
This operation is energy consuming, requires a complex mechanism and controls, is ineffective in the lowest heat source temperatures and especially so where the relative humidity of the heat source is high.
Where the conventional evaporator is employed as a heat exchanger in the circuit of a thermal transfer unit such as a heat pump, supplementary or auxiliary heating is added to complement the reduction or cessation of heat transfer through the conventional evaporator.
The aim of this invention is to provide a buffer between the heat source, which could be ambient air, and the evaporator in order that the evaporator may operate in a near moisture free environment in a thermally conductive hermetically sealed container.